[PATCH 1/22] Add drivers/mtd/devices/blockmtd.c
Gareth Bult (Encryptec)
Gareth at Encryptec.net
Tue Dec 21 08:42:41 EST 2004
Ok,
Gimmie a clue - what did you change ?
Gareth.
On Tue, 2004-12-21 at 14:39 +0100, Jörn Engel wrote:
> Jörn
>
> --
> When you close your hand, you own nothing. When you open it up, you
> own the whole world.
> -- Li Mu Bai in Tiger & Dragon
>
> Add your driver under a new name. There will be interface changes, so
> it needs to be renamed anyway.
>
> Signed-off-by: Jörn Engel <joern at wohnheim.fh-wedel.de>
> ---
>
> blockmtd.c | 647 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 647 insertions(+)
>
> --- /dev/null 2004-08-21 20:14:47.000000000 +0200
> +++ linux-2.6.9cow/drivers/mtd/devices/blockmtd.c 2004-12-20 18:56:51.000000000 +0100
> @@ -0,0 +1,647 @@
> +/*
> + * $Id: blkmtd.c,v 1.23 2004/08/09 14:03:19 dwmw2 Exp $
> + *
> + * blkmtd.c - use a block device as a fake MTD
> + *
> + * Author: Simon Evans <spse at secret.org.uk>
> + *
> + * Copyright (C) 2001,2002 Simon Evans
> + *
> + * Licence: GPL
> + *
> + * How it works:
> + * The driver uses raw/io to read/write the device and the page
> + * cache to cache access. Writes update the page cache with the
> + * new data and mark it dirty and add the page into a BIO which
> + * is then written out.
> + *
> + * It can be loaded Read-Only to prevent erases and writes to the
> + * medium.
> + *
> + */
> +
> +#include <linux/config.h>
> +#include <linux/module.h>
> +#include <linux/fs.h>
> +#include <linux/blkdev.h>
> +#include <linux/bio.h>
> +#include <linux/pagemap.h>
> +#include <linux/list.h>
> +#include <linux/init.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/buffer_head.h>
> +
> +#define err(format, arg...) printk(KERN_ERR "blkmtd: " format "\n" , ## arg)
> +#define info(format, arg...) printk(KERN_INFO "blkmtd: " format "\n" , ## arg)
> +#define warn(format, arg...) printk(KERN_WARNING "blkmtd: " format "\n" , ## arg)
> +#define crit(format, arg...) printk(KERN_CRIT "blkmtd: " format "\n" , ## arg)
> +
> +
> +/* Default erase size in K, always make it a multiple of PAGE_SIZE */
> +#define CONFIG_MTD_BLKDEV_ERASESIZE (128 << 10) /* 128KiB */
> +#define VERSION "$Revision: 1.23 $"
> +
> +/* Info for the block device */
> +struct blkmtd_dev {
> + struct list_head list;
> + struct block_device *blkdev;
> + struct mtd_info mtd_info;
> + struct semaphore wrbuf_mutex;
> +};
> +
> +
> +/* Static info about the MTD, used in cleanup_module */
> +static LIST_HEAD(blkmtd_device_list);
> +
> +static void blkmtd_sync(struct mtd_info *mtd);
> +
> +#define MAX_DEVICES 4
> +
> +/* Module parameters passed by insmod/modprobe */
> +char *device[MAX_DEVICES]; /* the block device to use */
> +int erasesz[MAX_DEVICES]; /* optional default erase size */
> +int ro[MAX_DEVICES]; /* optional read only flag */
> +int sync;
> +
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Simon Evans <spse at secret.org.uk>");
> +MODULE_DESCRIPTION("Emulate an MTD using a block device");
> +MODULE_PARM(device, "1-4s");
> +MODULE_PARM_DESC(device, "block device to use");
> +MODULE_PARM(erasesz, "1-4i");
> +MODULE_PARM_DESC(erasesz, "optional erase size to use in KiB. eg 4=4KiB.");
> +MODULE_PARM(ro, "1-4i");
> +MODULE_PARM_DESC(ro, "1=Read only, writes and erases cause errors");
> +MODULE_PARM(sync, "i");
> +MODULE_PARM_DESC(sync, "1=Synchronous writes");
> +
> +#define PAGE_READAHEAD 64
> +
> +void cache_readahead(struct address_space *mapping, int index)
> +{
> + filler_t *filler = (filler_t*)(mapping->a_ops->readpage);
> + int i,pagei;
> + unsigned ret = 0;
> + unsigned long end_index;
> + struct page *page;
> + LIST_HEAD(page_pool);
> + struct inode *inode = mapping->host;
> + loff_t isize = i_size_read(inode);
> +
> + if(!isize) {
> + printk(KERN_INFO "iSize=0 in cache_readahead\n");
> + return;
> + }
> +
> + end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
> +
> + spin_lock_irq(&mapping->tree_lock);
> + for(i=0;i<PAGE_READAHEAD;i++) {
> + pagei=index+i;
> + if (pagei > end_index) {
> + printk(KERN_INFO "Overrun end of disk in cache readahead\n");
> + break;
> + }
> + page = radix_tree_lookup(&mapping->page_tree, pagei);
> + if(page && (!i)) break;
> + if(page) continue;
> + spin_unlock_irq(&mapping->tree_lock);
> + page = page_cache_alloc_cold(mapping);
> + spin_lock_irq(&mapping->tree_lock);
> + if(!page) break;
> + page->index=pagei;
> + list_add(&page->lru, &page_pool);
> + ret++;
> + }
> + spin_unlock_irq(&mapping->tree_lock);
> + if(ret) {
> + read_cache_pages(mapping, &page_pool, filler, NULL);
> + //printk(KERN_INFO "Readahead [%d/%d] pages from [%d]\n",ret,PAGE_READAHEAD,index);
> + }
> +}
> +
> +static struct page* page_readahead(struct address_space *mapping, int index)
> +{
> + filler_t *filler = (filler_t*)(mapping->a_ops->readpage);
> + cache_readahead(mapping,index);
> + return read_cache_page(mapping, index, filler, NULL);
> +}
> +/**
> + * write_pages - write block of data to device via the page cache
> + * @dev: device to write to
> + * @buf: data source or NULL if erase (output is set to 0xff)
> + * @to: offset into output device
> + * @len: amount to data to write
> + * @retlen: amount of data written
> + *
> + * Grab pages from the page cache and fill them with the source data.
> + * Non page aligned start and end result in a readin of the page and
> + * part of the page being modified. Pages are added to the bio and then written
> + * out.
> + */
> +
> +static int write_pages(struct blkmtd_dev *dev, const u_char *buf, loff_t to, size_t len, size_t *retlen)
> +{
> + struct page *page;
> + struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;
> + //
> + int err = 0; // return status
> + int index = to >> PAGE_SHIFT; // page index
> + int offset = to & ~PAGE_MASK; // page offset
> + //
> +
> + static int my_read()
> + {
> + err=0;
> + page = page_readahead(mapping,index);
> + if( unlikely(!page) ) {
> + crit("unable to read page (%d) in write_pages\n",index);
> + err=-ENOMEM;
> + }
> + //if(IS_ERR(page)) err=-EIO;
> + if(err) printk("READ ERROR\n");
> + return err;
> + }
> + //
> + static int my_erase()
> + {
> + int pages = len >> PAGE_SHIFT;
> + unsigned char *p;
> + unsigned char *max;
> + int format;
> +
> + while(pages) {
> + //printk(KERN_INFO "readahead on index (%d)\n",index);
> + if(my_read()) return err;
> +
> + max = ((char*)page_address(page)+PAGE_SIZE);
> + format = 0;
> +
> + for(p=(unsigned char*)page_address(page); p<max; p++)
> + if(*p != 0xff) {
> + format=1;
> + break;
> + }
> +
> + if(format) {
> + //DEBUG(3, "write_pages: erasing\n");
> + lock_page(page);
> + memset(page_address(page), 0xff, PAGE_SIZE);
> + set_page_dirty(page);
> + unlock_page(page);
> + }
> + page_cache_release(page);
> + pages--;
> + index++;
> + }
> + *retlen = len;
> + return 0;
> + }
> +
> + static int my_write()
> + {
> + int cpylen;
> +
> + if(retlen) *retlen = 0;
> + //printk(KERN_INFO "Write req: %d\n",len);
> + while(len) {
> + if((offset+len) > PAGE_SIZE)
> + cpylen = PAGE_SIZE - offset; // multiple pages
> + else cpylen = len; // this page
> + len = len - cpylen;
> + //
> + // Get page
> + //
> + if(my_read()) return err;
> + //
> + if(memcmp(page_address(page)+offset,buf,cpylen)) {
> + lock_page(page);
> + memcpy(page_address(page) + offset,buf, cpylen);
> + set_page_dirty(page);
> + unlock_page(page);
> + }
> + page_cache_release(page);
> +
> + if(retlen) *retlen += cpylen;
> + //
> + buf+=cpylen;
> + offset = 0;
> + index++;
> + //
> + }
> + //printk(KERN_INFO "Write act: %d\n",*retlen);
> + return 0;
> + }
> +
> + err=0;
> + down(&dev->wrbuf_mutex);
> + err = buf ? my_write() : my_erase();
> + up(&dev->wrbuf_mutex);
> + return err;
> +}
> +
> +/* erase a specified part of the device */
> +static int blkmtd_erase(struct mtd_info *mtd, struct erase_info *instr)
> +{
> + struct blkmtd_dev *dev = mtd->priv;
> + struct mtd_erase_region_info *einfo = mtd->eraseregions;
> + int numregions = mtd->numeraseregions;
> + size_t from;
> + u_long len;
> + int err = -EIO;
> + size_t retlen;
> +
> + instr->state = MTD_ERASING;
> + from = instr->addr;
> + len = instr->len;
> +
> + /* check erase region has valid start and length */
> + //DEBUG(2, "blkmtd: erase: dev = `%s' from = 0x%zx len = 0x%lx\n", mtd->name+9, from, len);
> + while(numregions) {
> + DEBUG(3, "blkmtd: checking erase region = 0x%08X size = 0x%X num = 0x%x\n",
> + einfo->offset, einfo->erasesize, einfo->numblocks);
> + if(from >= einfo->offset
> + && from < einfo->offset + (einfo->erasesize * einfo->numblocks)) {
> + if(len == einfo->erasesize
> + && ( (from - einfo->offset) % einfo->erasesize == 0))
> + break;
> + }
> + numregions--;
> + einfo++;
> + }
> +
> + if(!numregions) {
> + /* Not a valid erase block */
> + err("erase: invalid erase request 0x%lX @ 0x%08zX", len, from);
> + instr->state = MTD_ERASE_FAILED;
> + err = -EIO;
> + }
> +
> + if(instr->state != MTD_ERASE_FAILED) {
> + /* do the erase */
> + DEBUG(3, "Doing erase from = %zd len = %ld\n", from, len);
> + err = write_pages(dev, NULL, from, len, &retlen);
> + if(err || retlen != len) {
> + err("erase failed err = %d", err);
> + instr->state = MTD_ERASE_FAILED;
> + } else {
> + instr->state = MTD_ERASE_DONE;
> + }
> + }
> +
> + DEBUG(3, "blkmtd: erase: checking callback\n");
> + mtd_erase_callback(instr);
> + DEBUG(2, "blkmtd: erase: finished (err = %d)\n", err);
> + return err;
> +}
> +
> +static int blkmtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
> +{
> + struct blkmtd_dev *dev = mtd->priv;
> + struct page *page;
> + //
> + int index = from >> PAGE_SHIFT;
> + int offset = from - (index << PAGE_SHIFT);
> + int cpylen;
> +
> + if(from > mtd->size) return -EINVAL;
> + if(from + len > mtd->size) len = mtd->size - from;
> +
> + if(retlen) *retlen = 0;
> +
> + while(len) {
> + if((offset+len) > PAGE_SIZE)
> + cpylen = PAGE_SIZE - offset; // multiple pages
> + else cpylen = len; // this page
> + len = len - cpylen;
> + //
> + // Get page
> + //
> + page = page_readahead(dev->blkdev->bd_inode->i_mapping,index);
> + if(!page) return -ENOMEM;
> + if(IS_ERR(page)) return -EIO;
> + //
> + memcpy(buf, page_address(page) + offset, cpylen);
> + page_cache_release(page);
> + //
> + if(retlen) *retlen += cpylen;
> + buf+=cpylen;
> + offset = 0;
> + index++;
> + //
> + }
> + return 0;
> +}
> +
> +
> +/* write data to the underlying device */
> +static int blkmtd_write(struct mtd_info *mtd, loff_t to, size_t len,
> + size_t *retlen, const u_char *buf)
> +{
> + struct blkmtd_dev *dev = mtd->priv;
> + int err;
> +
> + if(!len) return 0;
> + if(to >= mtd->size) return -ENOSPC;
> + if(to + len > mtd->size) len = mtd->size - to;
> +
> + err = write_pages(dev, buf, to, len, retlen);
> + if(err > 0) err = 0;
> + return err;
> +}
> +
> +
> +/* sync the device - wait until the write queue is empty */
> +static void blkmtd_sync(struct mtd_info *mtd)
> +{
> + sync_blockdev(((struct blkmtd_dev*)mtd->priv)->blkdev);
> + return;
> +}
> +
> +static void free_device(struct blkmtd_dev *dev)
> +{
> + DEBUG(2, "blkmtd: free_device() dev = %p\n", dev);
> + if(dev) {
> + if(dev->mtd_info.eraseregions)
> + kfree(dev->mtd_info.eraseregions);
> + if(dev->mtd_info.name)
> + kfree(dev->mtd_info.name);
> +
> + if(dev->blkdev) {
> + invalidate_inode_pages(dev->blkdev->bd_inode->i_mapping);
> + close_bdev_excl(dev->blkdev);
> + }
> + kfree(dev);
> + }
> +}
> +
> +
> +/* For a given size and initial erase size, calculate the number
> + * and size of each erase region. Goes round the loop twice,
> + * once to find out how many regions, then allocates space,
> + * then round the loop again to fill it in.
> + */
> +static struct mtd_erase_region_info *calc_erase_regions(
> + size_t erase_size, size_t total_size, int *regions)
> +{
> + struct mtd_erase_region_info *info = NULL;
> +
> + DEBUG(2, "calc_erase_regions, es = %zd size = %zd regions = %d\n",
> + erase_size, total_size, *regions);
> + /* Make any user specified erasesize be a power of 2
> + and at least PAGE_SIZE */
> + if(erase_size) {
> + int es = erase_size;
> + erase_size = 1;
> + while(es != 1) {
> + es >>= 1;
> + erase_size <<= 1;
> + }
> + if(erase_size < PAGE_SIZE)
> + erase_size = PAGE_SIZE;
> + } else {
> + erase_size = CONFIG_MTD_BLKDEV_ERASESIZE;
> + }
> +
> + *regions = 0;
> +
> + do {
> + int tot_size = total_size;
> + int er_size = erase_size;
> + int count = 0, offset = 0, regcnt = 0;
> +
> + while(tot_size) {
> + count = tot_size / er_size;
> + if(count) {
> + tot_size = tot_size % er_size;
> + if(info) {
> + DEBUG(2, "adding to erase info off=%d er=%d cnt=%d\n",
> + offset, er_size, count);
> + (info+regcnt)->offset = offset;
> + (info+regcnt)->erasesize = er_size;
> + (info+regcnt)->numblocks = count;
> + (*regions)++;
> + }
> + regcnt++;
> + offset += (count * er_size);
> + }
> + while(er_size > tot_size)
> + er_size >>= 1;
> + }
> + if(info == NULL) {
> + info = kmalloc(regcnt * sizeof(struct mtd_erase_region_info), GFP_KERNEL);
> + if(!info)
> + break;
> + }
> + } while(!(*regions));
> + DEBUG(2, "calc_erase_regions done, es = %zd size = %zd regions = %d\n",
> + erase_size, total_size, *regions);
> + return info;
> +}
> +
> +
> +extern dev_t __init name_to_dev_t(const char *line);
> +
> +static struct blkmtd_dev *add_device(char *devname, int readonly, int erase_size)
> +{
> + struct block_device *bdev;
> + int mode;
> + struct blkmtd_dev *dev;
> +
> + if(!devname)
> + return NULL;
> +
> + /* Get a handle on the device */
> +
> +
> +#ifdef MODULE
> + mode = (readonly) ? O_RDONLY : O_RDWR;
> + bdev = open_bdev_excl(devname, mode, NULL);
> +#else
> + mode = (readonly) ? FMODE_READ : FMODE_WRITE;
> + bdev = open_by_devnum(name_to_dev_t(devname), mode);
> +#endif
> + if(IS_ERR(bdev)) {
> + err("error: cannot open device %s", devname);
> + DEBUG(2, "blkmtd: opening bdev returned %ld\n", PTR_ERR(bdev));
> + return NULL;
> + }
> +
> + DEBUG(1, "blkmtd: found a block device major = %d, minor = %d\n",
> + MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev));
> +
> + if(MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
> + err("attempting to use an MTD device as a block device");
> + blkdev_put(bdev);
> + return NULL;
> + }
> +
> + dev = kmalloc(sizeof(struct blkmtd_dev), GFP_KERNEL);
> + if(dev == NULL) {
> + blkdev_put(bdev);
> + return NULL;
> + }
> +
> + memset(dev, 0, sizeof(struct blkmtd_dev));
> + dev->blkdev = bdev;
> + atomic_set(&(dev->blkdev->bd_inode->i_mapping->truncate_count), 0);
> + if(!readonly) {
> + init_MUTEX(&dev->wrbuf_mutex);
> + }
> +
> + dev->mtd_info.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
> +
> + /* Setup the MTD structure */
> + /* make the name contain the block device in */
> + dev->mtd_info.name = kmalloc(sizeof("blkmtd: ") + strlen(devname), GFP_KERNEL);
> + if(dev->mtd_info.name == NULL)
> + goto devinit_err;
> +
> + sprintf(dev->mtd_info.name, "blkmtd: %s", devname);
> + dev->mtd_info.eraseregions = calc_erase_regions(erase_size, dev->mtd_info.size,
> + &dev->mtd_info.numeraseregions);
> + if(dev->mtd_info.eraseregions == NULL)
> + goto devinit_err;
> +
> + dev->mtd_info.erasesize = dev->mtd_info.eraseregions->erasesize;
> + DEBUG(1, "blkmtd: init: found %d erase regions\n",
> + dev->mtd_info.numeraseregions);
> +
> + if(readonly) {
> + dev->mtd_info.type = MTD_ROM;
> + dev->mtd_info.flags = MTD_CAP_ROM;
> + } else {
> + dev->mtd_info.type = MTD_RAM;
> + dev->mtd_info.flags = MTD_CAP_RAM;
> + dev->mtd_info.erase = blkmtd_erase;
> + dev->mtd_info.write = blkmtd_write;
> + dev->mtd_info.writev = default_mtd_writev;
> + dev->mtd_info.sync = blkmtd_sync;
> + }
> + dev->mtd_info.read = blkmtd_read;
> + dev->mtd_info.readv = default_mtd_readv;
> + dev->mtd_info.priv = dev;
> + dev->mtd_info.owner = THIS_MODULE;
> +
> + list_add(&dev->list, &blkmtd_device_list);
> + if (add_mtd_device(&dev->mtd_info)) {
> + /* Device didnt get added, so free the entry */
> + list_del(&dev->list);
> + goto devinit_err;
> + } else {
> + info("mtd%d: [%s] erase_size = %dKiB %s [%ld]",
> + dev->mtd_info.index, dev->mtd_info.name + strlen("blkmtd: "),
> + dev->mtd_info.erasesize >> 10,
> + readonly ? "(read-only)" : "", PAGE_SIZE);
> + }
> + return dev;
> +
> + devinit_err:
> + free_device(dev);
> + return NULL;
> +}
> +
> +
> +/* Cleanup and exit - sync the device and kill of the kernel thread */
> +static void __devexit cleanup_blkmtd(void)
> +{
> + struct list_head *temp1, *temp2;
> +
> + /* Remove the MTD devices */
> + list_for_each_safe(temp1, temp2, &blkmtd_device_list) {
> + struct blkmtd_dev *dev = list_entry(temp1, struct blkmtd_dev,
> + list);
> + blkmtd_sync(&dev->mtd_info);
> + del_mtd_device(&dev->mtd_info);
> + info("mtd%d: [%s] removed", dev->mtd_info.index,
> + dev->mtd_info.name + strlen("blkmtd: "));
> + list_del(&dev->list);
> + free_device(dev);
> + }
> +}
> +
> +#ifndef MODULE
> +
> +/* Handle kernel boot params */
> +
> +
> +static int __init param_blkmtd_device(char *str)
> +{
> + int i;
> +
> + for(i = 0; i < MAX_DEVICES; i++) {
> + device[i] = str;
> + DEBUG(2, "blkmtd: device setup: %d = %s\n", i, device[i]);
> + strsep(&str, ",");
> + }
> + return 1;
> +}
> +
> +
> +static int __init param_blkmtd_erasesz(char *str)
> +{
> + int i;
> + for(i = 0; i < MAX_DEVICES; i++) {
> + char *val = strsep(&str, ",");
> + if(val)
> + erasesz[i] = simple_strtoul(val, NULL, 0);
> + DEBUG(2, "blkmtd: erasesz setup: %d = %d\n", i, erasesz[i]);
> + }
> +
> + return 1;
> +}
> +
> +
> +static int __init param_blkmtd_ro(char *str)
> +{
> + int i;
> + for(i = 0; i < MAX_DEVICES; i++) {
> + char *val = strsep(&str, ",");
> + if(val)
> + ro[i] = simple_strtoul(val, NULL, 0);
> + DEBUG(2, "blkmtd: ro setup: %d = %d\n", i, ro[i]);
> + }
> +
> + return 1;
> +}
> +
> +
> +static int __init param_blkmtd_sync(char *str)
> +{
> + if(str[0] == '1')
> + sync = 1;
> + return 1;
> +}
> +
> +__setup("blkmtd_device=", param_blkmtd_device);
> +__setup("blkmtd_erasesz=", param_blkmtd_erasesz);
> +__setup("blkmtd_ro=", param_blkmtd_ro);
> +__setup("blkmtd_sync=", param_blkmtd_sync);
> +
> +#endif
> +
> +
> +/* Startup */
> +static int __init init_blkmtd(void)
> +{
> + int i;
> +
> + info("version " VERSION);
> + /* Check args - device[0] is the bare minimum*/
> + if(!device[0]) {
> + err("error: missing `device' name\n");
> + return -EINVAL;
> + }
> +
> + for(i = 0; i < MAX_DEVICES; i++)
> + add_device(device[i], ro[i], erasesz[i] << 10);
> +
> + if(list_empty(&blkmtd_device_list))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +module_init(init_blkmtd);
> +module_exit(cleanup_blkmtd);
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